Fluid end manifolds and fluid end manifold assemblies

ABSTRACT

A fluid end manifold comprising a body having a front side and a back side, a first cylinder bore formed horizontally through the body, a second cylinder bore formed vertically through the body, a front mating face, and a back mating face, wherein the first and second cylinder bores intersect within the body to define an intersection region, wherein the front mating face is positioned on the front side of the body at a location corresponding to the intersection region, and wherein the back mating face is positioned on the back side of the body at a location corresponding to the intersection region.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 13/082,565, entitled “Fluid End Manifolds and FluidEnd Manifold Assemblies”, filed on Apr. 8, 2011.

BACKGROUND

The pump industry has used reciprocating pumps for many years to greateffect. However, over the years, the market has placed higher demands onreciprocating pumps to operate at higher flow rates and pressures and tohave longer operation lives. These market demands are pushing pumps tothe limits of current design and materials technology. One result ofthese market demands has been an increase in failures rates of fluid endmanifolds for reciprocating pumps.

Within the fluid end manifolds, several interactions are being realizedas the pump operates with the reciprocating cycle. During the pumpoperation, fluids are compressed within the fluid end manifold, creatingpositive pressure during pumping. After the compression cycle iscompleted, the reciprocating action continues creating a vacuum withinthe fluid end chamber which then draws fluid back into the fluid endmanifold. These pumps must operate continuously at speeds up to 350cycles per minute. Pressures generated within the fluid end manifoldscan be up to 20,000 psi or more.

Consequently, the fluid end manifold is constantly under variablestressing. This constant variable stressing may result in fatigue. It iswell known within the industry that fatigue has a significant effect onthe fluid end manifold life expectancy, often resulting in fatiguefailure of the fluid end manifolds. This fatigue failure may be a resultof the fluid end manifold flexing and/or ballooning under internalpressure loads. Fatigue failure may occur if the pressures realizedwithin the fluid end manifold are high enough to effect the materialstressing.

Thus, there is a need for an improved fluid end manifold assembly thatis able to withstand the variable stressing associated with highpressure pumps.

SUMMARY

The present invention relates to improved fluid end manifold assemblies.More particularly, the present invention relates to improved fluid endmanifolds and fluid end manifold assemblies adapted to utilizecompressive stresses as to minimize tensile stresses.

In one embodiment, the present invention provides a fluid end manifoldcomprising: a body having a front side and a back side; a first cylinderbore formed horizontally through the body; a second cylinder bore formedvertically through the body; a front mating face; and a back matingface, wherein the first and second cylinder bores intersect within thebody to define an intersection region, wherein the front mating face ispositioned on the front side of the body at a location corresponding tothe intersection region, and wherein the back mating face is positionedon the back side of the body at a location corresponding to theintersection region.

In another embodiment, the present invention provides a fluid endmanifold assembly comprising: a first fluid end manifold, wherein thefirst fluid end manifold comprises: a body having a front side and aback side; a first cylinder bore formed horizontally through the body; asecond cylinder bore formed vertically through the body; a front matingface; and a back mating face, wherein the first and second cylinderbores intersect within the body to define an intersection region,wherein the front mating face is positioned on the front side of thebody at location corresponding to the intersection region, and whereinthe back mating face is positioned on the back side of the body atlocation corresponding to the intersection region; and a second fluidend manifold, wherein the second fluid end manifold comprises: a bodyhaving a front side and a back side; a first cylinder bore formedhorizontally through the body; a second cylinder bore formed verticallythrough the body; a front mating face; and a back mating face, whereinthe first and second cylinder bores intersect within the body to definean intersection region, wherein the front mating face is positioned onthe front side of the body at location corresponding to the intersectionregion, and wherein the back mating face is positioned on the back sideof the body at location corresponding to the intersection region,wherein the first fluid end manifold and the second fluid end manifoldare positioned relative to one another so that the back mating face ofthe first fluid end manifold is in line with the front mating face ofthe second fluid end manifold.

In another embodiment, the present invention provides a method forinducing compressive stresses within a fluid end manifold comprising:providing a fluid end manifold, the fluid end manifold comprising: afront side and a back side; a first cylinder bore formed horizontallythrough the body; a second cylinder bore formed vertically through thebody; a front mating face; and a back mating face, wherein the first andsecond cylinder bores intersect within the body to define anintersection region, wherein the front mating face is positioned on thefront side of the body at location corresponding to the intersectionregion, and wherein the back mating face is positioned on the back sideof the body at location corresponding to the intersection region; andapplying a compressive force to the front mating face and the backmating face.

The features and advantages of the present invention will be readilyapparent to those skilled in the art. While numerous changes may be madeby those skilled in the art, such changes are within the spirit of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete and thorough understanding of the present embodimentsand advantages thereof may be acquired by referring to the followingdescription taken in conjunction with the accompanying drawings.

FIGS. 1A and 1B are illustrations depicting an embodiment of a fluid endmanifold of the present invention.

FIG. 2 is an illustration depicting an embodiment of a fluid endmanifold of the present invention.

FIGS. 3A and 3B are illustrations of an embodiment of a fluid endmanifold assembly of the present invention.

DETAILED DESCRIPTION

The present invention relates to improved fluid end manifold assemblies.More particularly, the present invention relates to improved fluid endmanifolds and fluid end manifold assemblies adapted to utilizecompressive stresses as to minimize tensile stresses.

There may be several potential advantages to the fluid end manifolds andthe fluid end manifold assemblies disclosed herein. One of the manypotential advantages of the fluid end manifolds and the fluid endmanifold assemblies disclosed herein is that they may provide a fluidend manifold and a fluid end manifold assembly that is able to resistfatigue failure more adequately than conventional fluid end manifoldsand conventional fluid end manifold assemblies. Another potentialadvantage of the fluid end manifolds and fluid end manifold assembliesdisclosed herein is that they may be able to operate at higher pressuresand flow rates than conventional fluid end manifolds and conventionalfluid end manifold assemblies.

Referring now to FIGS. 1A and 1B and FIG. 2, a fluid end manifold 10 inaccordance with one embodiment of the present invention is illustrated.As illustrated, fluid end manifold 10 includes body 20, front side 30,back side 40, first cylinder bore 50, second cylinder bore 60, frontmating face 70, and back mating face 80. First cylinder bore 50 andsecond cylinder bore 60 intersect in region 90 (as shown in FIG. 2).Fluid end manifold 10 may further include one or more front connectionsurfaces 100, one or more back connection surfaces 110, one or moreadditional cylinder bores 120, one or more front cross-bars 130, one ormore back cross-bars 140, and one or more hydraulic restraints 150.FIGS. 1A and 1B depict a fluid end manifold comprising two frontconnection surfaces 100, two back connection surfaces 110, twoadditional cylinder bores 120, one front cross-bar 130, one backcross-bar 140, and two hydraulic restraints 150.

In one embodiment, body 20 of fluid end manifold 10 may be constructedout of any suitable material to withstand pressures of up to 20,000 psiand temperatures up to 400° F. In some embodiments, body 20 may beconstructed out of any suitable material, preferably high tensilematerials. In some embodiments, body 20 may be constructed out of AISI4140 steel, AISI 4330 steel, or derivatives thereof. Body 20 may be ofany suitable shape or size. In some embodiments, body 20 may be anyshape which allows crossing of first cylinder bore 50 and secondcylinder bore 60. In certain embodiments, body 20 may be T shaped.

In some embodiments, fluid end manifold 10 may comprise first cylinderbore 50 and second cylinder bore 60. In some embodiments, first cylinderbore 50 may comprise a surface 55 (as shown in FIG. 2). In someembodiments, second cylinder bore 60 may comprise a surface 65 (as shownin FIG. 2). In some embodiments, first cylinder bore 50 may be ahorizontal cylinder bore. In some embodiments, second cylinder bore 60may be a vertical cylinder bore. First cylinder bore and second cylinderbore may be of any size. In some embodiments, first cylinder bore 50 andsecond cylinder bore are the same size. In some embodiments, firstcylinder bore and second cylinder bore 60 may be from 3.125 inches to 6inches in diameter. In some embodiments, first cylinder bore 50 and/orsecond cylinder bore 60 may extend all the way through body 20. In someembodiments, first cylinder bore 50 and/or second cylinder bore 60 mayonly extend through a portion of body 20. In some embodiments, firstcylinder bore 50 and second cylinder bore 60 may be perpendicular to oneanother. In some embodiments, first cylinder bore 50 and second cylinderbore 60 may intersect within body 20 to define intersection region 90(as shown in FIG. 2). In some embodiments, surface 55 of first cylinderbore 50 may be in contact with surface 65 of second cylinder bore 60 todefine one or more contacts points 95 (as shown in FIG. 2). In someembodiments intersection region 90 may be defined by a region comprisingcontact points 95. In some embodiments, intersection region 90 may bedefined as a circular shaped region of space having a diameter in aplane perpendicular to both first cylinder bore 50 and second cylinderbore 60 including contact points 95. In some embodiments, theintersection region 90 may include a midpoint 98 that is in the centerof intersection region 90.

In certain embodiments, fluid end manifold 10 may comprise front matingface 70 and back mating face 80. Front mating face 70 and back matingface 80 may be constructed out of any suitable high tensile material towithstand pressures of up to 20,000 psi and temperatures up to 400° F.In some embodiments, front mating face 70 and back mating face 80 may beconstructed out of AISI 4130 steel, AISI 4330 steel, or derivativesthereof. In some embodiments, front mating face 70 and back mating face80 may be constructed out of the same material as body 20. In otherembodiments, front mating face 70 and back mating face 80 may beconstructed out of a material different than body 20. In someembodiments, front mating face 70 and back mating face 70 may beconstructed out of the same material. In other embodiments, front matingface 70 and back mating face 80 may be constructed out of differentmaterials. In some embodiments, front mating face 70 and back matingface 80 may be a part of body 20.

Front mating face 70 and back mating face 80 may be of any suitableshape or size. In some embodiments, front mating face 70 and back matingface 80 may comprise flat surface 75 and flat surface 85, respectively.Flat surfaces 75 and 85 may be perpendicular to the plane formed byfirst cylinder bore 50 and second cylinder bore 60. In some embodiments,flat surfaces 75 and 85 may be circular shaped. In other embodiments,flat surfaces 75 and 85 may be ring shaped, comprising an outer diameterand an inner diameter. Flat surfaces 75 and 85 may be any size. In someembodiments, flat surfaces 75 and 85 may have an outer diameter that islarger than the diameter of intersection region 90. In some embodiments,flat surfaces 75 and 85 may have an inner diameter that is smaller thanthe diameter of intersection region 90. In some embodiments, flatsurfaces 75 and 85 may have an inner diameter of from about 1 inch toabout 6 inches. In some embodiments, flat surfaces 75 and 85 may have anouter diameter of from about 3.125 inches to about 9 inches. As shown inFIG. 1A, the center of flat surface 75 may define a point of space,center point 78. Similarly, the center of flat surface 85 may define apoint of space, center point 88 (not illustrated).

In certain embodiments, front mating face 70 may be positioned on frontside 30 of body 20. In certain embodiments, front mating face 70 may bepositioned on front side 30 of body 20 at a location corresponding toregion 90. In certain embodiments, front mating face 70 may bepositioned on front side 30 of body 20 at a location corresponding toregion 90 such that surface 75 occupies a circular region of space in aplane perpendicular to first cylinder bore 50 and second cylinder bore60 directly in line with region 90 (as shown in FIG. 2). In certainembodiments, front mating face 70 may be positioned on front side 30 ofbody 20 at a location corresponding to region 90 such that that centerpoint 78 of front mating face 70 is directly in line with midpoint 98with respect to a plane perpendicular to first cylinder bore 50 andsecond cylinder bore 60 (as shown in FIG. 2).

In certain embodiments, back mating face 80 may be positioned on backside 40 of body 20. In certain embodiments, back mating face 80 may bepositioned on back side 40 of body 20 at a location corresponding toregion 90. In certain embodiments, back mating face 80 may be positionedon back side 40 of body 20 at a location corresponding to region 90 suchthat surface 85 occupies a circular region of space in a planeperpendicular to first cylinder bore 50 and second cylinder bore 60directly in line with intersection region 90. In certain embodiments,back mating face 80 may be positioned on back side 40 of body 20 at alocation corresponding to region 90 such that that center point 88 ofback mating face 80 is directly in line with midpoint 98 with respect toa plane perpendicular to first cylinder bore 50 and second cylinder bore60.

In some embodiments, fluid end manifold 10 may comprise one or morefront connection surfaces 100 and one or more back connections surfaces110. Front connections surfaces 100 and back connections surfaces 110may be located on front side 30 of fluid end manifold 10 and back side40 of fluid end manifold 10, respectively. In some embodiments, fluidend manifold 10 may comprise 2 front connection surfaces 100 on oppositesides of front mating face 80 and 2 back connection surfaces 110 onopposite sides of back mating face 80, as shown in FIG. 1. Front andback connection surfaces 100 and 110 may be constructed out of anysuitable material capable of withstanding pressures of up to 20,000 psiand temperatures up to 400° F. In some embodiments, front and backconnection surfaces 100 and 110 may be constructed out of any suitablematerial, preferably high tensile materials. In some embodiments, frontand back connection surfaces 100 and 110 may be constructed of AISI 4140steel, AISI 4330 steel, or derivatives thereof. In some embodiments,front and back connection surfaces 100 and 110 may be constructed out ofthe same material as body 20, front mating face 70, and/or back matingface 80. In other embodiments, front connection surface 100 and backconnection surface 110 may be constructed out of a material differentthan body 20, front mating face 70, and/or back mating face 80. Frontand back connection surfaces 100 and 110 may be of any shape and size.In some embodiments, front and back connection surfaces 100 and 110 maycomprise flat surfaces.

In some embodiments, fluid end manifold 10 may comprise on or moreadditional cylinder bores 120. In some embodiments, additional cylinderbore 120 may be a horizontal cylinder bore. Additional cylinder 120 boremay be of any size. In some embodiments, additional cylinder bore 120may be from 0.75 inches to 2 inches in diameter. In some embodiments,additional cylinder bore 120 may extend all the way through body 20. Insome embodiments, in addition to extending all the way through body 20,additional cylinder bore 120 may extend through front connection surface100 and back connection surface 110.

In some embodiments, as shown in FIG. 1, fluid end manifold 10 maycomprise two additional cylinder bores 120, two front connectionssurfaces 100, and two back connections surfaces 110. As shown in FIG. 1,one of the additional cylinder bores 120 may extend through one of thefront connection surfaces 100, body 20, and one of the back connectionsurfaces 110 and the other additional cylinder bore 120 may extendthrough the other front connection surface 100, body 20, and the otherback connection surface 110.

In some embodiments, fluid end manifold 10 may comprise one or morefront cross-bars 130. In some embodiments, fluid end manifold 10 maycomprise one or more back cross-bars 140. Front cross-bar 130 and backcross-bar 140 may be constructed out of any suitable material towithstand pressures of up to 20,000 psi and temperatures up to 400° F.In some embodiments, front cross-bar 130 and back cross-bar 140 may beconstructed out of any suitable material, preferably high tensilematerials. In some embodiments, front cross-bar 130 and back cross-bar140 may be constructed of AISI 4130 steel, AISI 4140 steel, orderivatives thereof. In some embodiments, front cross-bar 130 and backcross-bar 140 may be constructed out of the same material as body 20,front and/or back mating faces 70 and 80, and/or front and/or backconnection surfaces 100 and 110. In other embodiments, front cross-bar130 and back cross-bar 140 may be constructed out of a materialdifferent than body 20, front and/or back mating faces 70 and 80, and/orfront and/or back connection surfaces 100 and 110. Front cross-bar 130and back cross-bar 140 may be of any shape and size. In someembodiments, front cross-bar 130 and back cross-bar 140 may comprisethreaded circular tie rods. In some embodiments, front cross-bar 130 maybe attached to the one or more front connection surfaces 100. In someembodiments, front cross-bar 130 may be attached to the one or morefront connection surfaces 100 by any means. In some embodiments, backcross-bar 140 may be attached to the one or more back connectionsurfaces 110. In some embodiments, back cross-bar 140 may be attached tothe one or more front connection surfaces 110 by any means. In someembodiments, front cross-bar 130 and back cross-bar 140 may be incontact with front mating face 70 and back mating face 80, respectively.

In some embodiments, fluid end manifold 10 may further comprise one ormore hydraulic restraints 150. In some embodiments, hydraulic restraint150 may comprise a tie rod. In other embodiments, hydraulic restraint150 may comprise a hydraulic cylinder. Still in other embodiments,hydraulic restraint 150 may comprise a leadscrew or a prestressed rod.In some embodiments, one or more hydraulic restraints 150 may be locatedin the one or more additional cylinder bores 120. In some embodiments,as shown in FIG. 1, the fluid end manifold 10 may comprise two hydraulicrestraints 150. In some embodiments, as shown in FIG. 1, the one or morehydraulic restraints 150 may be connected to one or more frontconnection surfaces 100 and one or more back connection surfaces 110.The hydraulic restraint 150 may be connected to the front and backconnection surfaces 100 and 110 by any means. In some embodiments, theone or more hydraulic restraints 150 may provide means for applyingcompressive forces to fluid end manifold 10. In some embodiments, thehydraulic restraint 150 may provide means for applying compression tothe fluid end manifold 10 by tightening the connections of the one ormore hydraulic restraints 150 to the one or more front and backconnection surfaces 100 and 110, thereby allowing compression to beapplied across front mating face 70 and back mating face 80. In someembodiments, upon activation, a rectangular frame may provide restraintto hydraulic cylinders to allow compressive forces to be exerted on thefluid end manifold. Still in other embodiments, a prestressed rod may beset into the additional cylinder bores 120 and attached to the front andback connection surfaces 100 and 110 using thermal expansion and then beallowed to cool to induce the compressive forces.

Referring now to FIGS. 3A and 3B, a fluid end manifold assembly 1000 inaccordance with one embodiment of the present invention is illustrated.Fluid end manifold assembly 1000 may comprise one or more fluid endmanifolds. In one embodiment, as illustrated in FIGS. 3A and 3B, fluidend manifold assembly 1000 may comprise a first fluid end manifold 2000,a second fluid end manifold 3000, and a third fluid end manifold 4000.Furthermore, as shown in FIG. 3B, fluid end assembly 1000 may comprise afourth fluid end manifold 5000 and a fifth fluid end manifold 6000. Insome embodiments, fluid end manifold assembly 1000 may comprise twofluid end manifolds. In other embodiments, fluid end manifold assemblymay comprise three fluid end manifolds. In other embodiments, fluid endmanifold assembly 1000 may comprise more than three fluid end manifolds.

In some embodiments, first fluid end manifold 2000, second fluid endmanifold 3000, and/or third fluid end manifold 4000 may comprise samecomponents as described above with respect to fluid end manifold 10. Insome embodiments, first fluid end manifold 2000 may include a body, afront side, a back side 2040, a first cylinder bore 2050, a secondcylinder bore 2060, a midpoint 2098, a front mating face 2070 with acenter point 2075, a back mating face 2080 with a center point 2085,front connection surfaces 2100, back connection surfaces 2110,additional cylinder bores 2120, and a front cross-bar 2130. In someembodiments, second fluid end manifold 3000 may include a body 3020, afront side 3030, a back side 3040, a first cylinder bore 3050, a secondcylinder bore 3060, a midpoint 3098, a front mating face 3070 with acenter point 3075, a back mating face 3080 with a center point 3085,front connection surfaces 3100, back connection surfaces 3110, andadditional cylinder bores 3120. In some embodiments, third fluid endmanifold 4000 may include a body 4020, a front side 4030, a back side4040, a first cylinder bore 4050, a second cylinder bore 4060, amidpoint 4098, a front mating face 4070 with a center point 4075, a backmating face 4080 with a center point 4085, front connection surfaces4100, back connection surfaces 4110, additional cylinder bores 4120, andback cross-bar 4130.

In certain embodiments, fluid end manifold assembly 1000 may compriseone or more hydraulic restraints 1150. Hydraulic restraints 1150 mayextend through the front connection surfaces 2100, 3100, and 4100,additional cylinder bores 2120, 3120, 4120, and back connection surfaces2110, 3110, and 4110. Hydraulic restraints may be attached to frontconnection surfaces 2100, 3100, and 4100 and back connection surfaces2110, 3110, and 4110.

In certain embodiments, fluid end manifold assembly 1000 may beconfigured such that one or more of front mating faces 2070, 3070, and4070, back mating faces 2080, 3080, and 4080, center points 2078, 2088,3078, 3088, 4078, and 4088, and midpoints 2098, 3098, and 4098 are inline. In one embodiment, front mating faces 2070, 3070, and 4070, backmating faces 2080, 3080, and 4080, center points 2078, 2088, 3078, 3088,4078, and 4088, and midpoints 2098, 3098, and 4098 may each be in line.

In some embodiments, fluid end manifold assembly 1000 may be configuredsuch that one or more of front mating faces 2070, 3070, and 4070 may bein contact with one or more of back mating faces 2080, 3080, and 4080.In some embodiments, fluid end manifold assembly 1000 may be configuredsuch that one or more of front connection surfaces 2100, 3100, and 4100may be in contact with one or more back connections surfaces 2110, 3110,and 4110. In one embodiment, fluid end manifold assembly 1000 may beconfigured such that back mating face 2080 is in contact with frontmating face 3070, back mating face 3080 is in contact with front matingface 4070, back connection surfaces 2110 are in contact with frontconnection surfaces 3100, and back connection surfaces 3110 are incontact with front connection surfaces 4100.

In some embodiments, fluid end manifold assembly 1000 may be configuredsuch that a compressive force may be applied against each of frontmating faces 2170, 3170, and 4170 and back mating faces. In someembodiments, fluid assembly 1000 may comprise two hydraulic restraints1150. In some embodiments, the one or more hydraulic restraint 1150 maybe connected to one or more front connection surfaces 2100 and one ormore back connection surfaces 4110. In one embodiment, front connectionsurfaces 2100 may be connected to one another by a front cross-bar 1130.In one embodiment, back connection surfaces 4110 may be connected to oneanother by a back cross-bar 1140. In some embodiments, front cross bar1130 may be in contact with front mating face 2070. In some embodiments,back cross bar 1140 may be in contact with back mating face 4080. Insome embodiments, a compressive force may be applied against each offront mating faces 2170, 3170, and 4170 and back mating faces 2180,3180, and 4180 by any means. In some embodiments, a compressive forcemay be applied against each of front mating faces 2170, 3170, and 4170and back mating faces 2180, 3180, and 4180 by tightening connections ofthe one or more hydraulic restraints 1150 to front connection surface2100 and back connection surface 4110. In some embodiments, acompressive force may be applied against each of front mating faces2170, 3170, and 4170 and back mating faces 2180, 3180, and 4180 byutilizing a rectangular frame which upon activation may providerestraint to hydraulic cylinders disposed within the additional cylinderbores 2120, 3120, and 4120 to allow compressive forces to be exerted onthe fluid end manifold assembly. Still in other embodiments, aprestressed rod may be set into the additional cylinder bores 2120,3120, and 4120 and attached to the front surface 2100 and backconnection surface 4110 using thermal expansion and then be allowed tocool to induce the compressive forces.

In some embodiments, the present invention provides a method forinducing compressive stresses within a fluid end manifold. In someembodiments, the fluid end manifold may be fluid end manifold asdescribed above. In some embodiments, the present invention provides amethod for inducing a compressive stress within a fluid end manifoldassembly. In some embodiments, the fluid end manifold assembly may be afluid end manifold assembly as described above. In some embodiments, thepresent invention provides a method for inducing a compressive stresswithin a fluid end manifold or a fluid end manifold assembly by applyingcompressive forces in regions of high stress. In some embodiments, theregions of high stress may correspond to an intersection region of twocylinder bores in a fluid end manifold as described above. In someembodiments, applying compressive forces in the regions of high stressmay be accomplished by applying compressive forces to mating facespositioned in the region of high stress. The mating faces may comprisemating faces as described above and may be positioned one the fluidbodies as described above. Compressive forces may be applied to themating faces as described above.

Without wishing to be limited to theory, it is believed that theapplication of compressive forces along the mating faces of the fluidend manifolds may achieve compressive loading within the fluid endmanifold, especially within the regions subject to high stress when inoperation. Regions subject to high stress include the regions where thesurfaces of the cylinder bores intersect. This compressive loading mayreduce the natural tendency for these regions of the fluid end manifoldto flex while under operation and reduce the tensile stresses of thoseregions. The ring shaped mating faces described herein are believed tooffer an additional advantage of allowing areas inside the ring shape toflex. While not wishing to be limited to theory, it is believed that thering areas provide contact interface between each fluid end manifoldthat corresponds with an internal expansion area of the fluid endmanifold. When the internal pressure is applied, the area of the ringsare under compression which results in a reduction of stress level atthe key bore intersection points. In certain embodiments, areas insideof the ring shape are not under compression, or are under lesscompression than the areas covered by the rings, and able to flex andexpand.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalternations can be made herein without departing from the spirit andscope of the invention as defined by the following claims.

What is claimed is:
 1. A fluid end manifold assembly comprising: a firstfluid end manifold, wherein the first fluid comprises: a body having afront side and a back side; a first cylinder bore formed horizontallythrough the body; a second cylinder bore formed vertically through thebody; a front mating face; and a back mating face, wherein the first andsecond cylinder bores intersect within the body to define anintersection region, wherein the front mating face is positioned on thefront side of the body at location corresponding to the intersectionregion, and wherein the back mating face is positioned on the back sideof the body at location corresponding to the intersection region; and asecond fluid end manifold, wherein the second fluid end manifoldcomprises: a body having a front side and a back side; a first cylinderbore formed horizontally through the body; a second cylinder bore formedvertically through the body; a front mating face; and a back matingface, wherein the first and second cylinder bores intersect within thebody to define an intersection region, wherein the front mating face ispositioned on the front side of the body at location corresponding tothe intersection region, and wherein the back mating face is positionedon the back side of the body at location corresponding to theintersection region, wherein the first fluid end manifold and the secondfluid end manifold are positioned relative to one another so that theback mating face of the first fluid end manifold is in line with thefront mating face of the second fluid end manifold.
 2. The fluid endmanifold assembly of claim 1, wherein the first fluid end manifold andthe second fluid end manifold are positioned relative to one another sothat the back mating face of the first fluid end manifold is in contactwith the front mating face of the second fluid end manifold.
 3. Thefluid end manifold assembly of claim 2, wherein the front mating faceand the back mating face of the first fluid end manifold and the frontmating face and the back mating face of the second fluid end manifoldcomprise a ring shaped portion.
 4. The fluid end manifold assembly ofclaim 3, wherein: the ring shaped portion of the front mating face ofthe first fluid end manifold and the ring shaped portion of the backmating face of the first fluid end manifold are positioned at locationscorresponding to the intersection region of the first fluid end manifoldand the ring shaped portion of the front mating face of the second fluidend manifold and the ring shaped portion of the back mating face of thesecond fluid end manifold are positioned at locations corresponding tothe intersection region of the second fluid end manifold.
 5. The fluidend manifold assembly of claim 4, wherein: the body of the first fluidend manifold further comprises at least one front connection surface andat least one back connection surface and the body of the second fluidend manifold further comprises at least one front connection surface andat least one back connection surface.
 6. The fluid end manifold assemblyof claim 5, wherein: the body of the first fluid end manifold comprisesa first front connection surface, a second front connection surface, afirst back connection surface, and a second back connection surface andthe body of the second fluid end manifold comprises a first frontconnection surface, a second front connection surface, a first backconnection surface, and a second back connection surface.
 7. The fluidend manifold assembly of claim 6, wherein: the body of the first fluidend manifold further comprises a third cylinder bore and a fourthcylinder bore, wherein the third cylinder bore extends through the bodyfrom the first front connection surface to the first back connectionsurface and wherein the fourth cylinder bore extends through the bodyfrom the second front connection surface to the second back connectionsurface and the body of the second fluid end manifold further comprisesa third cylinder bore and a fourth cylinder bore, wherein the thirdcylinder bore extends through the body from the first front connectionsurface to the first back connection surface and wherein the fourthcylinder bore extends through the body from the second front connectionsurface to the second back connection surface.
 8. The fluid end manifoldassembly of claim 7, wherein: the body of the first fluid end manifoldfurther comprises a front cross-bar, the front cross-bar being connectedto the first front connection surface and the second front connectionsurface, and the body of the second fluid end manifold further comprisesa back cross-bar, the back cross-bar being connected to the first backconnection surface and the second back connection surface.
 9. The fluidend manifold of assembly of claim 8, wherein the fluid end manifoldassembly further comprises a first hydraulic restraint connected to thefirst front connection surface of the first fluid end manifold and thefirst back connection surface of the second fluid end manifold and asecond hydraulic restraint connected to the second front connectionsurface of the first fluid end manifold and the second back connectionsurface of the second fluid end manifold.
 10. The fluid end manifoldassembly of claim 9, wherein the front cross-bar is in contact with thefront mating face of the first fluid end manifold and wherein the secondcross-bar is in contact with the back mating face of the second fluidend manifold.
 11. A method for inducing compressive stresses within afluid end manifold comprising: providing a fluid end manifold, the fluidend manifold comprising: a front side and a back side; a first cylinderbore formed horizontally through the body; a second cylinder bore formedvertically through the body; a front mating face; and a back matingface, wherein the first and second cylinder bores intersect within thebody to define an intersection region, wherein the front mating face ispositioned on the front side of the body at location corresponding tothe intersection region, and wherein the back mating face is positionedon the back side of the body at location corresponding to theintersection region; and applying a compressive force to the frontmating face and the back mating face.